CVE-2024-26483 is a high-severity arbitrary file upload vulnerability identified in the Profile Image module of Kirby CMS version 4.1.0. Kirby CMS is a flat-file content management system used for building websites. The vulnerability allows an unauthenticated attacker to upload a crafted PDF file that can lead to arbitrary code execution on the server hosting the CMS. This occurs because the Profile Image module does not properly validate or sanitize uploaded files, enabling the attacker to bypass restrictions and upload malicious payloads embedded within PDF files. The vulnerability is classified under CWE-94 (Improper Control of Generation of Code), indicating that the system improperly handles user-supplied input that leads to code injection or execution. The CVSS 3.1 base score is 8.8, reflecting high impact with network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), but requiring user interaction (UI:R). The vulnerability affects confidentiality, integrity, and availability (C:H/I:H/A:H), meaning successful exploitation can lead to full system compromise, data theft, and service disruption. No patches or vendor advisories are currently linked, and no known exploits in the wild have been reported as of the publication date (February 22, 2024). However, the ease of exploitation and high impact make this a critical issue for organizations using Kirby CMS 4.1.0, especially those exposing the Profile Image upload functionality to external users or the internet at large.

For European organizations using Kirby CMS version 4.1.0, this vulnerability poses a significant risk. Exploitation can lead to complete server compromise, allowing attackers to execute arbitrary code, potentially leading to data breaches, defacement, ransomware deployment, or lateral movement within internal networks. Organizations in sectors such as government, finance, healthcare, and media that rely on Kirby CMS for public-facing websites or intranet portals are particularly vulnerable. The compromise of these systems could result in loss of sensitive personal data protected under GDPR, leading to regulatory penalties and reputational damage. Additionally, service disruption caused by exploitation could impact business continuity and customer trust. Since the vulnerability requires user interaction (uploading a crafted PDF), organizations with user-upload features or public registration portals are at higher risk. The absence of known exploits in the wild currently reduces immediate threat but does not eliminate the risk of future exploitation, especially given the low complexity and no privilege requirements.

1. Immediate upgrade or patching: Organizations should monitor Kirby CMS official channels for patches or updates addressing this vulnerability and apply them promptly once available. 2. Restrict file upload types: Implement strict server-side validation to allow only safe image formats (e.g., JPEG, PNG) for profile images, explicitly blocking PDFs and other potentially dangerous file types. 3. Implement file scanning: Use antivirus and malware scanning solutions on all uploaded files to detect malicious payloads before processing or storing them. 4. Harden web server configurations: Disable execution permissions on directories used for file uploads to prevent execution of uploaded malicious files. 5. Employ Content Security Policy (CSP) and Web Application Firewalls (WAF): Configure CSP to restrict script execution and deploy WAF rules to detect and block suspicious upload attempts. 6. Monitor logs and alerts: Continuously monitor web server and application logs for unusual upload activity or errors related to file handling. 7. Limit user interaction exposure: If possible, restrict or disable public file upload features until the vulnerability is mitigated. 8. Conduct security awareness: Educate users and administrators about the risks of uploading untrusted files and encourage reporting of suspicious activity. These measures, combined, reduce the attack surface and limit the potential for exploitation even before an official patch is released.